jumpinjoe
Hellcat
Well thought out and all good candidates!!!Gave this a bit of thought and personally I would consider most iconic as a firearm that even non gun people recognize they are that iconic and visible/used in media and by others. Even if they do not know the proper name they recognize the firearm.
Some examples would be I believe,
Luger
1911
Colt "peacemaker"
Sw Snubbie known colloquially as the "38"
There are others.